a good buddy just got a 07 duramax lmz old body style he is hoping for some more fuel economy what do you guys think about 4'mbrp exquast diablo predator programmer and the air box mod.good start or is there a beterr route to go. any input would be great thanks.

 

The predator is a good tuner for the $$$,that should be a good start.

 

just go straight to efi or ppe. i kick myself in the head every time i think about it now, and i just put a 4 inch turbo back with 6 inch stacks on today from mbrp, and they are sick.......